PATIENTS AND METHODS: A total of 184 patients with PTC were included in the study.RESULTS: There were 24 patients with SPC and nine with PTC and two other primary tumours (42 additional malignancies in total). Additional tumours were more prevalent in male and older patients. In 11 cases (33%), the two carcinomas were synchronous. PTCs from synchronous cases were significantly larger than those from non-synchronous cases.CONCLUSION: Patients with PTC were at elevated risk for SPC. In one third of patients, both neoplasms were diagnosed within the same year. Male and older patients were more likely to have SPC.